Sir,

After treatment of complicated retinal detachment using silicone oil,1, 2, 3 recurrent detachment may still occur secondary to open retinal breaks with or without reproliferation.4, 5, 6, 7 Conventional treatment involves removal of preexisting silicone oil followed by vitreoretinal manipulations and reinjection of oil. Recently, simplified procedures have been advocated for limited proliferation.8, 9 We conducted a retrospective study on 13 cases in which vitreous surgery was performed under preexisting silicone oil without infusion of physiological solution. The surgical indications, techniques, and anatomical outcomes were evaluated.

All patients were treated by a single surgeon (CM Yang) from July 2002 to October 2004 at National Taiwan University Hospital. Cases were selected based on the preoperative assessment, which predicted that reattachment may be obtained without resorting to the use of vitreous cutter. All cases presented with inferior rhegmatogenous retinal detachment with or without macular involvement and localized posterior or anterior vitreoretinal proliferation.

For eyes with absent or inadequate inferior scleral buckle, a high buckle was obtained either by inferior reinforcement of a segmental silicone sponge, or by inferior shortening of the polytetrafluoroethylene (PTFE) band, if it had been used in the previous surgery.10, 11 Three sclerotomies were created; the infusion line was connected to air pump in stead of balanced salt solution (BSS) bottle. Retinal traction was released by epiretinal membrane peeling or inferior circumferential relaxing retinotomy using pics, forceps, or scissors. Prominent subretinal bands were also removed through iatrogenic retinotomy. Air-subretinal fluid exchange through preexisting or iatrogenic breaks was performed. Endophotocoagulation around the break margins or in areas of suspected breaks was then executed after the retina became flattened. Silicone oil (Acri. Sil-oI 5000, Acri.Tec GmbH, Glienicke bei, Berlin) infusion to replace the air bubble was undertaken before closing the sclerotomy wounds. Scleral buckle reinforcement was not performed in three cases: one because of preexisting high buckle; the other two because of severe inferior tenon adhesion.

The patients’ characteristics were presented in Table 1. All cases in this series had complete retinal reattachment in the previous operation; most developed recurrent detachment involving the periphery in 2–4 weeks after the previous operation; and all experienced slow progression of the detachment. Open breaks were identified in only half of the cases. All cases obtained successful retinal reattachment at the end of the operation. None of the operated cases had persistent postoperative perisilicone haemorrhage, high intraocular pressure, rubeosis iridis, or increased turbidity or accelerated emulsification of mixed oil. Except one case which developed recurrent detachment requiring further surgery, the remaining 12 cases had persistent attached retina throughout the follow-up periods. An example was shown in Figure 1.

Table 1 Clinical data of the 13 cases in the study
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Figure 1
figure 1

Case 4, recurrent retinal detachment after initial operation. (a) Silicone oil was filled in the vitreous cavity, and the macula was attached. (b) Detached retina with posterior PVR change was noted in the inferior nasal quadrant. (c) After inferior scleral buckle reinforcement and vitreous surgery under silicone oil, the posterior pole remained attached. (d) High inferior buckle was seen and the inferior retina became reattached.

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Comment

The combined external and internal approaches utilized in this study have several advantages. First, the part of the retina which was attached preoperatively stayed attached throughout the process, thus increasing the likelihood of at least maintaining the preoperative visual acuity in the treated eye. Second, without removing the oil, the operation time is considerably reduced. Third, as oil may hold the retina in place, membrane removal is actually enhanced. Fourth, approaches from both outside and inside the eye ensure more complete release of retinal traction, thus theoretically reducing the chance of rubeosis or recurrent retinal detachment if silicone oil removal is considered. Admittedly, inferior high buckle placement alone may be adequate in treating simple inferior peripheral break without significant proliferation.12 However, buckling alone is not useful when there has already been a high buckle in place; severe tissue adhesion around the previous buckle may prevent buckle reinforcement. The limitation of this method is in treating cases with significant and widespread proliferating tissue or cases with tented retina and large breaks with possible subretinal oil. The presence of the crystalline lens was not found to be a contraindication for this technique. In performing this technique, adequate diathermy to the lower peripheral retinal vessels should be performed before retinotomy to decrease the possibility of bleeding and postoperative recurrent reproliferation.13 For an adequate and complete drainage, a larger than usual drainage retinotomy or more than one retinotomies may be necessary. We prefer the use of air–fluid exchange followed by oil–air exchange to direct oil–fluid exchange using silicone oil pump connected to the infusion line,8, 14 because, by using the air pump with fixed pressure, intraocular pressure may be better controlled.9 In addition, by monitoring the air entering the vitreous cavity, the start and the end of the drainage process may be better recognized. The duration of the inferior detachment in each case varied greatly in this series. Our results indicated that the severity of reproliferation was more important than the detachment duration to affect the surgical outcome.

In conclusion, in this small series, the results seemed to support the concept that, with proper preoperative fundus assessment, combined inferior buckle and vitreous surgery under the preexisting silicone oil may be a simplified and useful method to treat recurrent inferior retinal detachment without extensive proliferation in silicone oil-filled eyes.